Disazo compound and ink composition containing the same

ABSTRACT

Problems The present invention provides an ink composition which, when applied as an ink-jet recording solution to plain paper and processed glossy paper, assumes vivid yellow color and gives printed material excellent in light fastness, gas fastness and moisture fastness. Means for Solving the Problems 
 
Ink-jet printing with an ink-jet ink composition containing a disazo compound represented by the following formula (1) can give a vivid yellow-colored product excellent in light fastness, gas fastness and moisture fastness  
                 
         (in the formula (1), X represents specific diamine residue; and Y 1  and Y 2  each represent an alkylamino group substituted with a sulfonic acid group and/or a carboxyl group, a phenoxy group substituted with a sulfonic acid group and/or a carboxyl group and an anilino group substituted with a sulfonic acid group and/or a carboxyl group).

TECHNICAL FIELD

The present invention relates to a recording solution, a water-basedyellow ink composition and an ink-jet recording method, and a new disazocompound.

BACKGROUND OF THE INVENTION

Diverse ink jetting processes have been developed for the recordingmethod by means of ink-jet printer, and the process respectivelycomprises generating ink droplets to deposit onto various recordingmaterials (such as paper, film, cloth) for recording. The recordingmethod by means of ink-jet printer is characterized in that it createsno machine noise due to the mechanism in which a recording head does notcontact with the recording material. Such a method, being characterizedby readily providing a compact, high-speed and color printer, hasrapidly been spread in recent years and further propagation may beexpected in the future. In order to record in color an image informationor a character information displayed on a computer color monitor bymeans of an ink-jet printer, the information is generally printedaccording to subtractive color mixing of inks of four colors, namelythose are yellow(Y), magenta(M), cyan(C) and black(K). In order toreproduce an printed image created by additive color mixing of R, G andB on a CRT display as faithfully as possible according to subtractivecolor mixing, the dyestuff to use, especially those for each Y, M and Cinks, are desired to have vividness and color hues close to thestandards of Y, M and C respectively. Additionally, it is required thatthe resulting ink composition is stable for long-term storage, and theprinted image has high optical density and excellent fastness includingwater fastness, light fastness and gas fastness.

The use of ink-jet printers has diversely been propagated from compactones for OA to large ones for industrial use. Therefore, more fastnessesincluding water fastness and light fastness are desired. The waterfastness has substantially been being improved by coating inorganicmicro particles such as porous silica, cationic polymer, alumina sol orspecial ceramics which can absorb dyestuff in ink, on a paper sheettogether with PVA resin. However, the moisture fastness during storageof a printed matter such as a photograph is required to be improvedfurther. Technology for substantially improving light fastness is notyet established. Especially among four primary colors of Y, M, C and K,a yellow dyestuff having vivid hue and excellent light fastness andmoisture fastness is not available and its improvement is a criticalsubject.

With a digital camera becoming popular lately, there are more chances toprint an image to obtain a photograph at home. Color change of such aphotograph during storage caused by an oxidant gas in the air is seen asa problem. With regard to a yellow recording solution, color changingand fading caused by light (light fastness) and blot of an image causedby water and moisture (water fastness, moisture fastness) pose technicalproblems and many solutions have been proposed.

Patent Literatures 1 to 5, for example, disclose compounds havingsimilar structure to that of a disazo compound of the present invention,but do not provide a yellow dyestuff which, when applied to plain paperand processed glossy paper for ink-jet recording, give vivid hue andprinted material excellent in light fastness, gas fastness and moisturefastness.

Patent Literature 1: JAPANESE LAID OPEN PATENT-1992/252270

Patent Literature 2: JAPANESE LAID OPEN PATENT-1996/325493

Patent Literature 3: JAPANESE LAID OPEN PATENT-1998/279858

Patent Literature 4: JAPANESE LAID OPEN PATENT-2000/144003

Patent Literature 5: JAPANESE PUBLISHED PATENT-1980/11708

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention

It is an object of the present invention to provide an ink compositionwhich, when applied to ink-jet recording and recording by a writingimplement in plain paper and processed glossy paper, gives vivid hue andprinted material excellent in light fastness, gas fastness and moisturefastness, and a dyestuff suitable for preparing the ink composition.

Means for Solving the Problems

The inventors of the present invention have found, after havingintensively studied a way to solve the above mentioned problems, that anink composition containing a disazo compound having specific structurecan solve the above problems, and thus completed the present invention.

In more detail, the present invention relates to:(1) A disazo compound represented by the following formula (1), in afree acid form:

{wherein, X represents a group represented by the formula (2):

(Z in the formula (2) represents an alkylene group of 1 to 6 carbonatoms that may be substituted with one alkyl group of 1 to 3 carbonatoms depending on circumstances; R₁ and R₂ in the formula (2) representeach independently a hydrogen atom or an alkyl group of 1 to 3 carbonatoms); Y₁ and Y₂ represent each an alkylamino group substituted with asulfonic acid group and/or a carboxyl group, a phenoxy group substitutedwith a sulfonic acid group and/or a carboxyl group or an anilino groupsubstituted with a sulfonic acid group and/or a carboxyl group}.(2) The disazo compound according to (1), wherein X in formula (1) isone selected from a group consisting of NHC₂H₄NH, NHC₃H₆NH, NHCH(CH₃)CH₂NH, NHC₂H₄N(CH₃), NHC₃H₆N(CH₃), NHC(CH₃) ₂CH₂NH, NHC₂H₄N(C₂H₅),N(CH₃) C₂H₄N(CH₃) and NHC₃H₆N(C₃H₇).(3) The disazo compound according to (1) or (2), wherein X in formula(1) is NHC₂H₄NH.(4) The disazo compound according to any one of (1) to (3), wherein Y₁and Y₂ in formula (1) is NHC₂H₄SO₃H.(5) A disazo compound represented by the following formula (4), in afree acid form:

(6) A recording solution containing a aqueous medium and at least onekind of the disazo compound according to any one item of (1) to (5).(7) An ink composition comprising the recording solution according to(6).(8) An ink-jet ink composition comprising the recording solutionaccording to (6).(9) An ink-jet recording method wherein ink droplets are dischargedaccording to a record signal to record on recording material,characterized by using, as an ink, the ink-jet ink composition accordingto (8).(10) The ink-jet recording method according to (9) wherein the recordingmaterial is an information transmitting sheet.(11) An ink-jet printer equipped with a container containing the ink-jetink composition according to (8) and(12) A colored product colored by the ink-jet printer according to (11).

EFFECT OF THE INVENTION

The disazo compound of the present invention represented by the aboveformula (1) is extremely excellent insolubility in water andcharacterized in that an aqueous solution thereof has good keepingstability and good filtering characteristics with a membrane filter in aproduction process of an ink composition. The ink composition of thepresent invention containing the disazo compound has good storagestability without crystallization, physical property change, colorchange, and the like after long-term storage. A printed matter obtainedby using the ink composition of the present invention as a yellow inkfor ink-jet recording is excellent in light fastness, ozone fastness andmoisture fastness and thus excellent ink-jet recording can be obtained.As mentioned above, the ink composition of the present invention isextremely useful as a yellow ink for ink-jet recording.

BEST MODES FOR CARRYING OUT THE INVENTION

The present invention will be described in detail.

The disazo compound (a dyestuff) of the present invention is representedby the following general formula (1), in a free acid form:

{wherein, X represents a group represented by the formula (2):

(Z in the formula (2) represents an alkylene group of 1 to 6 carbonatoms that may be substituted with one alkyl group of 1 to 3 carbonatoms depending on circumstances; R₁ and R₂ in the formula (2) representeach independently a hydrogen atom or an alkyl group of 1 to 3 carbonatoms); Y₁ and Y₂ represent each an alkylamino group substituted with asulfonic acid group and/or a carboxyl group, a phenoxy group substitutedwith a sulfonic acid group and/or a carboxyl group or an anilino groupsubstituted with a sulfonic acid group and/or a carboxyl group}.

Specific example of X in formula (1) includes, for example, NHC₂H₄NH,NHC₃H₆NH, NHCH(CH₃) CH₂NH, NHC₂H₄N(CH₃), NHC₃H₆N(CH₃), NHC(CH₃)₂CH₂NH,NHC₂H₄N(C₂H₅), N(CH₃) C₂H₄N(CH₃), NHC₃H₆N(C₃H₇), NHC₃H₆NH, NHC₄H₈NH,NHC₅H₁₀NH, NH(CH₂)₃C₂H₄NH, NH₃H₆NH₂, NHCH₂C₃H₆CH₂NH, and NHC₂H₄NH isespecially preferable.

Specific example of Y₁, Y₂ in formula (1) includes, for example,NHC₂H₄SO₃H, NHCH₂COOH, NHC₂H₄COOH and N(CH₂COOH)₂.

It is especially preferable when both Y₁ and Y₂ are NHC₂H₄SO₃H.

The compound represented by formula (1) is produced, for example, asfollows. The monoazo compound represented by the following formula (A)and cyanuric chloride are condensed (primary condensation) to obtain acompound represented by the following formula (B). The compound of theformula (B) and amines represented by the formula (C1) and/or theformula (C2) are then condensed (secondary condensation) to obtain acompound represented by the formula (D1) and/or the formula (D2). Thecompound represented by the formula (D1) and/or the formula (D2) and acompound represented by the formula (E) are then condensed (tertiarycondensation) to obtain the object compound represented by the aboveformula (1). In the following formulae (C1), (C2), (D1), (D2) and (E),Y₁, Y₂ and X represent the same as in the above formula (1), and asulfonic acid group is represented in a free acid form.

The above primary, secondary and tertiary condensation reactions arepreferably carried out at 0 to 10° C. and pH 1 to 7, 20 to 70° C. and pH3 to 9, and 80 to 95° C. and pH 4 to 10, respectively. Water is usuallyused as a reaction medium in these reactions.

Specific examples of the compounds (dyestuffs) represented by theformula (1) are shown in Table 1 below, although the compounds of thepresent invention are not limited thereto. A sulfonic acid group and acarboxyl group are represented in a free acid form. TABLE 1 X Y₁ Y₂  1NHC₂H₄NH NHC₂H₄SO₃H NHC₂H₄SO₃H  2 NHC₂H₄NH NHCH₂COOH NHCH₂COOH  3NHC₂H₄NH NH(CH₂COOH)₂ N(CH₂COOH)₂  4 NHC₃H₆NH NHC₂H₄SO₃H NHC₂H₄SO₃H  5NHC₃H₆NH NHCH₂COOH N(CH₂COOH)₂  6 NHCH(CH₃)CH₂NH NHC₂H₄SO₃H NHC₂H₄SO₃H 7 NHC₂H₄N(CH₃) NHC₂H₄SO₃H NHC₂H₄SO₃H  8 NHC₃H₆N(CH₃) NHCH₂COOHNHCH₂COOH  9 NHC(CH₃)₂CH₂NH NHC₂H₄SO₃H NHC₂H₄SO₃H 10 NHC₂H₄N(C₂H₅)NHC₂H₄SO₃H NHC₂H₄SO₃H 11 N(CH₃)C₂H₄N(CH₃) NHCH₂COOH NHCH₂COOH 12NHC₃H₆N(C₃H₇) NHC₂H₄SO₃H NHC₂H₄SO₃H 13 NHC₄H₈NH NHC₂H₄SO₃H NHC₂H₄SO₃H 14NHC₅H₁₀NH N(CH₂COOH)₂ N(CH₂COOH)₂ 15 NH(CH₂)₃CH(CH₃)CH₂NH NHCH₂COOHNHCH₂COOH 16 NHCH₂C(CH₃)₂CH₂NH NHCH₂COOH NHCH₂COOH 17 NHC₆H₁₂NHNHC₂H₄SO₃H NHC₂H₄SO₃H 18 NHC₃H₆N(C₃H₇) NHC₂H₄SO₃H NHCH₂COOH No. X Y₁ Y₂19 NHC₂H₄NH

20 NHC₂H₄NH

21 NHC₂H₄NH

22 NHC₃H₆NH

23 NHC₃H₆NH

24 NHCH(CH₃)CH₂NH

25 NHC₂H₄N(CH₃)

26 NHC₃H₆N(CH₃)

27 NHC(CH₃)₂CH₂NH

28 NHC₂H₄N(C₂H₅)

29 N(CH₃)C₂H₄N(CH₃)

30 NHC₃H₆N(C₃H₇)

The above compound of the present invention can be used in a free acidform or a salt form thereof. The salt includes an alkali metal salt oran alkylamine salt, an alkanolamine salt, or an ammonium saltrepresented by the following formula (3):

(wherein, Z₁, Z₂, Z₃ and Z₄ represent each independently a hydrogenatom, an alkyl group, a hydroxyalkyl group or a hydroxyalkoxyalkylgroup).

Preferable salts include an alkali metal salt such as a sodium salt, apotassium salt and a lithium salt, an alkanolamine salt such as amonoethanolamine salt, a diethanolamine salt, a triethanolamine salt, amonoisopropanolamine salt, a diisopropanolamine salt and atriisopropanolamine salt and an ammonium salt. A sodium salt, forexample, is obtained as a wet cake by adding sodium chloride into thereaction solution of the compound obtained above to salt out and thenfiltering. The above wet cake is dissolved again in water and thenhydrochloric acid is added thereto to adjust pH 1 to 2 and thus obtainedcrystals are filtered to obtain a free acid (or a partly remainingsodium salt). The wet cake in the free acid form is alkalified by theaddition of, for example, potassium hydroxide, lithium hydroxide andammonia water under stirring along with water to obtain a potassiumsalt, a lithium salt and an ammonium salt, respectively.

The ink composition of the present invention is prepared by dissolvingthe compound of the present invention represented by the above formula(1) or a salt thereof in water or an aqueous solvent (water containing awater-soluble organic solvent (including a solution assistant, samehereinafter) to be described later). The compound represented by theabove formula (4) is especially preferably used. The approximate pH ofthe ink composition is preferably 6 to 11. When the ink composition isused for an ink-jet printer, a dyestuff component having low content ofan inorganic compound such as a chloride and a sulfate of a metal cationis preferable and the approximate standard of the content is, forexample, 1% by mass or less of the total amount of sodium chloride andsodium sulfate. For preparing a compound (a dyestuff component) havinglow content of inorganic compounds, a desalting treatment by, forexample, an ordinary method using a reverse osmosis membrane or a methodwhere a dried material or a wet cake of the dyestuff component of thepresent invention is stirred in a mixed solvent of methanol and water,filtered and dried in required times is repeated. The ink composition isused as a yellow ink, but may be mixed with other dyestuffs within arange not to impair the spirit of the present invention.

The ink composition of the present invention is prepared using water asa medium. The compound of the above formula (1) obtained by the methoddescribed above is contained usually by 0.3 to 8% by mass in the inkcomposition of the present invention. The water-soluble organic solventis also contained as needed in the ink composition of the presentinvention within a range not to impair the effect of the presentinvention. The water-soluble organic solvent may be used together with adye-dissolving agent, a dryness inhibitor (a wetting agent), a viscositymodifier, a penetrating agent, a surface tension modifier, anantifoaming agent, and the like. Other ink preparation agents include,for example, known additives such as a preservative and fungicide, a pHadjusting agent, a chelating agent, an antirust agent, an ultravioletabsorber, a viscosity modifier, a dye-dissolving agent, a fadinginhibitor, an emulsion stabilizer, a surface tension modifier, anantifoaming agent, a dispersing agent and a dispersion stabilizer.Content of the water-soluble organic solvent is usually 0 to 60% by massand preferably 10 to 50% by mass, while content of the ink preparationagent is usually 0 to 20% by mass and preferably 0 to 15% by mass.

Example of aqueous organic solvent includes, for example, alkanol havingcarbon number C1 to C4 such as methanol, ethanol, n-propanol,isopropanol, n-butanol, isobutanol, sec-butanol, tert-butanol;carboxylic acid amide such as N,N-dimethylformamide, orN,N-dimethylacetamide; heterocyclic ketone such as 2-pyrrolidone,N-methyl-2-pyrrolidone, 1,3-dimethylimidazolidine-2-one, or1,3-dimethylhexahydropyrimido-2-one; ketone or ketoalcohol such asacetone, methyl ethyl ketone, 2-methyl-2-hydroxypentane-4-one; cyclicether such as tetrahydrofuran, dioxane; monomer, oligomer orpolyalkylene glycol or thioglycol having carbon number C2 to C6 alkyleneunit such as ethylene glycol, 1,2- or 1,3-propylene glycol, 1,2- or1,4-butylene glycol, 1,6-hexylene glycol, diethylene glycol, triethyleneglycol, tetraethylene glycol, dipropylene glycol, thiodiglycol,polyethylene glycol, polypropylene glycol; or polyol(triol) such asglycerin, hexane-1,2,6-triol; (C1 to C4)alkyl ether of polyhydricalcohol such as ethylene glycol monomethyl ether, or ethylene glycolmonoethyl ether, diethylene glycol monomethyl ether, or diethyleneglycol monoethyl ether, or triethylene glycol monomethyl ether, ortriethylene glycol monoethyl ether; γ-butyrolactone, ordimethylsulfoxide.

Among them, isopropanol, glycerin, mono, di or triethylene glycol,dipropylene glycol, 2-pyrrolidone, N-methyl-2-pyrrolidone is preferable.Isopropanol, glycerin, diethylene glycol, 2-pyrrolidone are morepreferable. The aqueous organic solvent can be used alone or incombination with other solvents.

Preservative and fungicide includes, for example, organosulfur type,organonitrogensulfur type, organohalogen type, haloarylsulfone type,iodopropargyl type, N-haloalkylthio type, benzthiazole type, nitriletype, pyridine type, 8-oxyquinoline type, benzothiazole type,isothiazoline type, dithiol type, pyridine oxide type, nitropropanetype, organic tin type, phenol type, quaternary ammonium type, triazinetype, thiadiazine type, anilide type, adamantane type, dithiocarbamatetype, brominated indanone type, benzyl bromoacetate type, inorganic saltcompound.

Organohalogen type compound includes, for example, pentachlorophenolsodium; pyridine oxide type compound includes, for example,2-pyridinethiol-1-oxide sodium; inorganic salt compound includesanhydrous sodium acetate; isothiazoline type compound includes, forexample, 1,2-benzisothiazoline-3-one, 2-n-octyl-4-isothiazoline-3-one,5-chloro-2-methyl-4-isothiazoline-3-one,5-chloro-2-methyl-4-isothiazoline-3-one magnesium chloride,5-chloro-2-methyl-4-isothiazoline-3-one calcium chloride,2-methyl-4-isothiazoline-3-one calcium chloride. The other preservativeand fungicide includes, for example, sodium sorbate, sodium benzoate(Proxel GXL(S), Proxel XL-2 (S), etc. manufactured by Abesia Co., Ltd.).

Any substance would be optionally used as pH adjusting agent if thissubstance makes it possible to control pH of ink composition in therange of 6.0 to 11.0 to improve the preservation stability of inkcomposition.

pH adjusting agent includes, for example, alkanol amine such asdiethanol amine, triethanol amine; alkali metal hydroxide such aslithium hydroxide, sodium hydroxide, potassium hydroxide; ammoniumhydroxide, or alkali metal carbonate such as lithium carbonate, sodiumcarbonate, potassium carbonate.

Chelating reagent includes, for example, tetrasodium ethylenediaminetetraacetate, trisodium nitrilotriacetate, trisodiumhydroxyethylethylenediamine triacetate, pentasodium diethylenetriaminepentaacetate, disodium uramildiacetate. Rust preventive agent includes,for example, hydrogensulfite, sodium thiosulfate, ammoniumthioglycollate, diisopropylammonium nitrite, pentaerythritoltetranitrate, dicyclohexylammonium nitrite.

Ultraviolet absorber includes, for example, benzophenone type compounds,benzotriazole type compounds, cinnamic acid type compounds, stilbenetype compounds, or benzoxazole type compounds which emit a fluorescenceby absorbing ultraviolet ray, what is called fluorescent brightners.

Viscosity modifier includes aqueous organic solvent, and aqueous highmolecular compound such as polyvinyl alcohol, cellulose derivative,polyamine, polyimine. Dye solubilizing agent includes, for example,urea, ε-caprolactam, ethylene carbonate.

Fading inhibitor can be used to improve the storage stability of image.Various organic or metal complex fading-inhibitors can be used as afading-inhibitor. Organic fading-inhibitor includes hydroquinones,alkoxyphenols, dialkoxyphenols, phenols, anilines, amines, indanes,chromans, alkoxyanilines, heterocycles. Metal complex includes nickelcomplex, zinc complex.

Surface tension modifier includes a surface active agent, for example,anionic surface active agent, ampholytic surface active agent, cationicsurface active agent, nonionic surface active agent and so on. Anionicsurface active agent includes alkylsulfo carboxylate, α-olefinsulfonate, polyoxyethylene alkyl ether acetate, N-acylamino acid and itssalt, N-acylmethyl taurine, alkyl sulfate polyoxyalkyl ether sulfate,alkyl sulfate polyoxyethylene alkyl ether phosphate, rosin acid soap,castor oil sulfate, lauryl alcohol sulfate, alkylphenol type phosphate,alkyl type phosphate, alkyl aryl sulfonate, diethyl sulfosuccinate,diethylhexyl sulfosuccinate, dioctyl sulfosuccinate. Cationic surfaceactive agent includes 2-vinylpyridine derivatives, poly(4-vinylpyridine) derivatives. Ampholytic surface active agent includeslauryldimethylaminoacetic acid betaine,2-alkyl-N-carboxymethyl-N-hydroxyethyl imidazolinium betaine, palm oilfatty acid amide propyldimethylamino acetic acid betaine,polyoctylpolyaminoethyl glycine, and other imidazoline derivatives.

Nonionic surface active agent includes ether type compounds such aspolyoxyethylene nonylphenyl ether, polyoxyethylene octylphenyl ether,polyoxyethylene dodecylphenyl ether, polyoxyethylene octylphenyl ether,polyoxyethylene oleyl ether, polyoxyethylene lauryl ether,polyoxyethylene alkyl ether, polyoxyaralkyl alkyl ether; ester typecompounds such as polyoxyethylene oleic acid, polyoxyethylene oleate,polyoxyethylene distearate, sorbitan laurate, sorbitan monosterate,sorbitan monooleate, sorbitan sesquioleate, polyoxyethylene monooleate,polyoxyethylene stearate; acetylene glycol type compounds such as2,4,7,9-tetramethyl-5-decyn-4,7-diol, 3,6-dimethyl-4-octyn-3,6-diol,3,5-dimethyl-1-hexyn-3-ol (for example, Surfynol-104E, 104PG50, 82,465;Olfin STG, etc. manufactured by Nissin Chemical Industry Co., Ltd.). Theink preparation agent can be used alone or in combination with othermodifiers. Surface tension of ink composition in this invention isusually 25 to 70 mN/m, and is preferably 25 to 60 mN/m. Viscosity of inkcomposition in this invention is regulated 30 mPa·s or less, andpreferably 20 mPa·s or less.

The ink composition of the present invention is prepared by adding thecompound of the above formula (1), and as necessary, the abovewater-soluble organic solvent and the ink preparation agent toimpurity-free water such as distilled water and mixing these and mixing.Impurities may be filtered off from the ink composition obtained thus,if necessary.

Recording material to be used in the ink-jet recording method of thepresent invention includes, for example, an information transmittingsheet such as paper and film, fiber and leather. The informationtransmitting sheet is preferably surface-treated, specifically providedwith an ink receiving layer. The ink receiving layer is provided by, forexample, impregnating a cationic polymer into the substrate mentionedabove or coating it on the above substrates with a cationic polymer, orcoating inorganic particles such as porous silica, alumina sol andspecial ceramics that are able to adsorb dyestuffs in ink, together witha hydrophilic polymer such as polyvinyl alcohol and polyvinylpyrrolidone on the substrate mentioned above. Such sheets provided withthese ink receiving layers are usually called a professional paper(film) for ink-jet use or glossy paper (film) and are available on themarket as, for example, Pictorico (made by Asahi Glass Company), ColorBJ paper, Color BJ photofilm sheet (both made by Canon Inc.), Paper forcolor image jet (made by Sharp Corporation), Glossy film professionalfor superfine use (made by Seiko Epson Corporation) and Pictafine (madeby Hitachi Maxell Corporation). Plain paper without such an inkreceiving layer can naturally be used.

With regard to fiber, cellulose fiber or polyamide fiber such as nylon,silk and wool is preferable, and nonwoven fabric and cloth arepreferable. A dyestuff can be fixed inside fiber by applying the inkcomposition of the present invention to the fiber, preferably using anink-jet method and then adding a fixing step for wet-heating (forexample, at about 80 to 120° C.) or dry-heating (for example, at about150 to 180° C.). The dyed fiber obtained thus has excellent vividness,light fastness and washing fastness.

The ink-jet printer of the present invention is equipped with acontainer containing the above water-based ink composition at the inktank section thereof. The colored product of the present invention iscolored with the above ink composition containing the disazo compoundrepresented by the above formula (1) or the salt thereof.

The ink composition containing the disazo compound of the presentinvention can give recorded material especially excellent in lightfastness and also excellent in ozone fastness and moisture fastness. Itgives a greenish yellow color, which has suitable hue as a yellow colorfor ink-jet recording. Use of the above ink composition along with otherinks such as magenta and cyan can give colors of a broad visible range.Use of the above ink composition along with known magenta, cyan andblack excellent in light fastness, ozone fastness and moisture fastnesscan give recorded material excellent in light fastness, ozone fastnessand moisture fastness.

EXAMPLES

The present invention will be described more specifically with Examples.“Parts” and “%” in the description are based on mass unless otherwisestated.

Example 1

Cyanuric chloride of 18.4 parts and4-(3-sulfophenylazo)-2-methoxyaniline of 30.1 parts were subjected toprimary condensation at pH 5 to 6.5 and at 3 to 10° C. in an aqueoussolvent. Then, taurine of 13.5 parts was added to the reaction mixturesand secondary condensation carried out at pH 6 to 9 and at 40 to 70° C.After heated to 80° C., the product of the secondary condensation wassubjected to tertiary condensation at pH 8 to 10 and at 80 to 90° C. byadding ethylenediamine of 4 parts dropwise in 15 to 30 minutes. As a pHadjusting agent, a 10% aqueous solution of sodium carbonate was used inthe primary, secondary and tertiary condensation. Thus obtained productwas subjected to salting-out preferably at not higher than 60° C. andthen controlled to pH 2 to 4 with hydrochloric acid, followed byfiltration to obtain 54 parts of a disazo compound (λ_(max)=391 nm inwater) in a free acid form represented by the following formula (4).

Example 2

Cyanuric chloride of 18.4 parts and4-(3-sulfophenylazo)-2-methoxyaniline of 30.1 parts were subjected toprimary condensation at pH 5 to 6.5 and at 3 to 10° C. in an aqueoussolvent. Then, 5-sulfoanthranilic acid of 23.9 parts was added to thereaction mixtures and secondary condensation carried out at pH 6 to 9and at 40 to 70° C. After heated to 80° C., the product of the secondarycondensation was subjected to tertiary condensation at pH 8 to 10 and at80 to 90° C. by adding ethylenediamine of 4 parts dropwise in 15 to 30minutes. As a pH adjusting agent, a 10% aqueous solution of sodiumcarbonate was used in the primary, secondary and tertiary condensation.Thus obtained product was subjected to salting-out preferably at nothigher than 60° C. and then controlled to pH 2 to 4 with hydrochloricacid, followed by filtration to obtain 64 parts of a disazo compound(λ_(max)=392 nm in water) in a free acid form represented by thefollowing formula (5).

Example 3

(A) Preparation of Ink

The solution of the composition shown in Table 2 below, containing thedisazo compound (a dyestuff component) obtained in Example 1 or 2 wasprepared and filtered with a 0.45 μm membrane filter to obtain eachwater-based yellow ink composition for ink-jet printing. Ion-exchangewater was used. Water and ammonium hydroxide were added so that the pHof the ink composition is 8 to 10 and the total amount is 100 parts.TABLE 2 Each dyestuff component obtained in Example 1 or 2 3.0 parts(subjected to desalting) Water + ammonium hydroxide 77.9 parts Glycerin5.0 parts Urea 5.0 parts N-methyl-2-pyrrolidone 4.0 parts IPA (isopropylalcohol) 3.0 parts Butylcarbitol 2.0 parts Surface active agent(SURFYNOL 104PG 50 made by 0.1 parts Nissin Chemical Industry Co. Ltd.)Total 100.0 parts(B) Ink-Jet Printing

Ink-jet recording is carried out on four kinds of recording materials ofplain paper, Professional photo paper (PR-101 (made by Canon Inc.)),Photo glossy film (HG-201 (made by Canon Inc.)) and Paper for PM photo<gloss> (made by SEIKO EPSON CORP.), using an ink-jet printer (Tradename: BJ S-630 from Canon Inc.) (hereinafter, described as follows, PR:Professional photo paper, HG: Photo glossy film, PM: Paper for PMphoto).

(C) Evaluation of Recorded Image

(1) Evaluation of hue

Hue and vividness of a recorded image: L*, a*, and b* values of therecorded papers were measured using a calorimetric system (GretagMacbeth SpectroEye: made by GRETAG Corp.). Vividness was calculated fromchromaticity (a*, b*) using the equation: C*=((a*)²+(b*)²)^(1/2) andevaluated.

The results are shown in Table 3.

(2) Test for light fastness

The recorded image was irradiated at 24° C. and 60% RH for 50 hoursusing a xenon weather meter (made by Atlas Corp.). Densities (D values)of the images before and after the irradiation were measured by means ofthe above calorimetric system.

Residual ratio (%)=D value after irradiation/D value before irradiation

The calculated results are shown in Table 3.

(3) Test for ozone fastness

A sample piece having a recorded image printed on the sample piece wasleft for standing at 24° C., 12 ppm and 60% RH for 2 hours using anozone weather meter (Model OMS-H made by Suga Test Instruments Co.,Ltd.). Densities (D values) before and after the test were measured.Residual ratio (%)=D value after irradiation/D value before irradiationThe calculated results are shown in Table 3.(4) A sample piece having a recorded image printed on the sample piecefor a moisture fastness test was left for standing at 50° C. and 90% RHfor 150 hours in a thermo-hygrostat (made by Ouyou giken sangyou Corp.).Bleeding degrees before and after the test was evaluated by visualinspection. The results of evaluation were classified as follows and areshown in Table 3.

◯: No bleeding is observed.

Δ: Bleeding is a little observed.

X: Bleeding is seriously observed.

Test results on hue, light fastness, ozone fastness and moisturefastness of a recorded image are shown in Table 3. The results ofevaluation of the ink composition prepared using the compound obtainedin Example 1 are referred to Evaluation Example 1, and similarly theresults of evaluation of the ink composition prepared using the compoundobtained in Example 2 are referred to Evaluation Example 2. The compoundrepresented by the following formula (6) and the compound represented bythe following formula (7) were used as Comparative Example 1 andComparative Example 2 and those were evaluated at the same opticaldensity as those of Evaluation Examples 1 and 2 in the composition shownin Table 2. The results were shown in Table 3. Data show evaluationresults under the condition that density (D value) is about 1.0 ingradation printing.

TABLE 3 Vivid- Light Ozone Recording ness Hue Fast- Fast- MoistureMaterial C* L* a* b* ness ness Fastness Evaluation Plain 70.9 89.6 −3.170.8 97 99 ◯ Example 1 Paper PR 58.4 94.8 −8.4 57.8 98 93 ◯ HG 55.0 93.9−8.5 54.3 91 91 ◯-Δ PM 54.1 95.1 −10.2  53.1 95 96 ◯ Evaluation Plain71.6 89.0 −1.6 71.6 97 99 ◯ Example 2 Paper PR 57.9 95.0 −8.6 57.3 96 94◯ HG 56.4 94.1 −7.8 55.9 88 92 ◯ PM 58.4 95.1 −10.4  57.5 92 96 ◯Comparative Plain 62.7 89.1 −1.4 62.7 78 99 ◯ Example 1 Paper PR 60.995.2 −8.4 60.3 80 89 ◯ HG 61.9 94.4 −8.1 61.4 67 91 ◯-Δ PM 62.2 94.6−9.8 61.4 86 97 ◯-Δ Comparative Plain 68.6 88.7 −0.4 68.6 81 98 ◯Example 2 Paper PR 64.9 95.4 −8.4 64.4 82 82 ◯ HG 64.1 94.0 −7.7 63.6 6374 Δ PM 68.9 95.0 −9.8 68.2 94 97 XLight fastness and ozone fastness are shown in residual ratio %.

As apparent from Table 3, it can be understood that judging from avalues and the b* values, the Evaluation Examples show similar hue tothe Comparative Examples, and judging from C* values, the EvaluationExamples show similar vividness to the Comparative Examples and in plainpaper, the Evaluation Examples are more vivid than the ComparativeExamples. It can be said that the Evaluation Examples 1 and 2 show vividyellow similar to the dyestuffs of the Comparative Examples 1 and 2,which are typical yellow dyestuffs used for ink-jet printing. Withregard to light fastness, the Evaluation Examples 1 and 2 have higherresidual ratios, showing remarkable improvement. With regard to ozonefastness and moisture fastness, too, the Evaluation Examples 1 and 2 arebetter than the Comparative Examples 1 and 2. It can be understood thatthe disazo compound of the present invention has preferable hue as ayellow dyestuff for ink-jet printing and is a compound suitable forfurther improving storage stability of printed matter.

The disazo compound of the present invention is superior in inkproperties as a whole and has stable high-quality in each medium (arecording agent). In addition, each dyestuff obtained in Examples 1 and2 has solubility of not less than 100 g/l in water under an alkalinecondition (pH=8-9), and thus can give a stable ink as a dyestuff forink-jet printing and also can give a high-concentration ink. Therefore,the dyestuff has a broad use and is a compound easy-to-use.

INDUSTRIAL APPLICABILITY

The ink composition of the present invention can be prepared safely andinexpensively as various recording solutions, especially a yellow-inkrecording solution for an ink-jet printer, and an aqueous solutionthereof is excellent in storage stability and printing properties. Theprinted matter shows vivid yellow color and is superior in lightfastness, ozone fastness and moisture fastness.

1. A disazo compound represented by the following formula (1), in a freeacid form:

{wherein, X represents a group represented by the formula (2):

(Z in the formula (2) represents an alkylene group of 1 to 6 carbonatoms that may be substituted with one alkyl group of 1 to 3 carbonatoms depending on circumstances; R₁ and R₂ in the formula (2) representeach independently a hydrogen atom or an alkyl group of 1 to 3 carbonatoms); Y₁ and Y₂ represent each an alkylamino group substituted with asulfonic acid group and/or a carboxyl group, a phenoxy group substitutedwith a sulfonic acid group and/or a carboxyl group or an anilino groupsubstituted with a sulfonic acid group and/or a carboxyl group}.
 2. Thedisazo compound according to claim 1, wherein X represented in formula(1) is one selected from a group consisting of NHC₂H₄NH, NHC₃H₆NH,NHCH(CH₃) CH₂NH, NHC₂H₄N(CH₃), NHC₃H₆N(CH₃), NHC(CH₃)₂CH₂NH,NHC₂H₄N(C₂H₅), N(CH₃) C₂H₄N(CH₃), and NHC₃H₆N(C₃H₇).
 3. The disazocompound according to claim 1 or claim 2, wherein X represented informula (1) is NHC₂H₄NH.
 4. The disazo compound according to any one ofclaim 1 to claim 3, wherein Y₁ and Y₂ represented in formula (1) isNHC₂H₄SO₃H.
 5. A disazo compound represented by the following formula(4), in a free acid form:


6. A recording solution containing an aqueous medium and at least onekind of the disazo compound according to any one claims 1 to
 5. 7. Anink composition comprising the recording solution according to claim 6.8. An ink composition for ink-jet recording, comprising the recordingsolution according to claim
 6. 9. An ink-jet recording method whereinink droplets are discharged according to a record signal to record onrecording material, characterized by using, as an ink, the inkcomposition for ink-jet recording according to claim
 8. 10. The ink-jetrecording method according to claim 9 wherein the recording material isan information transmitting sheet.
 11. An ink-jet printer equipped witha container containing the ink composition for ink-jet recordingaccording to claim
 8. 12. A colored product colored by the ink-jetprinter according to claim 11.